/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: Param.java,v 1.2.4.1 2005/09/02 11:03:42 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.classfile.Field;
import com.sun.org.apache.bcel.internal.generic.BranchHandle;
import com.sun.org.apache.bcel.internal.generic.CHECKCAST;
import com.sun.org.apache.bcel.internal.generic.IFNONNULL;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
import com.sun.org.apache.bcel.internal.generic.Instruction;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.bcel.internal.generic.PUTFIELD;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ObjectType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Morten Jorgensen
 * @author Erwin Bolwidt <ejb@klomp.org>
 * @author John Howard <JohnH@schemasoft.com>
 */
final class Param extends VariableBase {

  /**
   * True if this Param is declared in a simple named template.
   * This is used to optimize codegen for parameter passing
   * in named templates.
   */
  private boolean _isInSimpleNamedTemplate = false;

  /**
   * Display variable as single string
   */
  public String toString() {
    return "param(" + _name + ")";
  }

  /**
   * Set the instruction for loading the value of this variable onto the
   * JVM stack and returns the old instruction.
   */
  public Instruction setLoadInstruction(Instruction instruction) {
    Instruction tmp = _loadInstruction;
    _loadInstruction = instruction;
    return tmp;
  }

  /**
   * Set the instruction for storing a value from the stack into this
   * variable and returns the old instruction.
   */
  public Instruction setStoreInstruction(Instruction instruction) {
    Instruction tmp = _storeInstruction;
    _storeInstruction = instruction;
    return tmp;
  }

  /**
   * Display variable in a full AST dump
   */
  public void display(int indent) {
    indent(indent);
    System.out.println("param " + _name);
    if (_select != null) {
      indent(indent + IndentIncrement);
      System.out.println("select " + _select.toString());
    }
    displayContents(indent + IndentIncrement);
  }

  /**
   * Parse the contents of the <xsl:param> element. This method must read
   * the 'name' (required) and 'select' (optional) attributes.
   */
  public void parseContents(Parser parser) {

    // Parse 'name' and 'select' attributes plus parameter contents
    super.parseContents(parser);

    // Add a ref to this param to its enclosing construct
    final SyntaxTreeNode parent = getParent();
    if (parent instanceof Stylesheet) {
      // Mark this as a global parameter
      _isLocal = false;
      // Check if a global variable with this name already exists...
      Param param = parser.getSymbolTable().lookupParam(_name);
      // ...and if it does we need to check import precedence
      if (param != null) {
        final int us = this.getImportPrecedence();
        final int them = param.getImportPrecedence();
        // It is an error if the two have the same import precedence
        if (us == them) {
          final String name = _name.toString();
          reportError(this, parser, ErrorMsg.VARIABLE_REDEF_ERR, name);
        }
        // Ignore this if previous definition has higher precedence
        else if (them > us) {
          _ignore = true;
          copyReferences(param);
          return;
        } else {
          param.copyReferences(this);
          param.disable();
        }
      }
      // Add this variable if we have higher precedence
      ((Stylesheet) parent).addParam(this);
      parser.getSymbolTable().addParam(this);
    } else if (parent instanceof Template) {
      Template template = (Template) parent;
      _isLocal = true;
      template.addParameter(this);
      if (template.isSimpleNamedTemplate()) {
        _isInSimpleNamedTemplate = true;
      }
    }
  }

  /**
   * Type-checks the parameter. The parameter type is determined by the
   * 'select' expression (if present) or is a result tree if the parameter
   * element has a body and no 'select' expression.
   */
  public Type typeCheck(SymbolTable stable) throws TypeCheckError {
    if (_select != null) {
      _type = _select.typeCheck(stable);
      if (_type instanceof ReferenceType == false && !(_type instanceof ObjectType)) {
        _select = new CastExpr(_select, Type.Reference);
      }
    } else if (hasContents()) {
      typeCheckContents(stable);
    }
    _type = Type.Reference;

    // This element has no type (the parameter does, but the parameter
    // element itself does not).
    return Type.Void;
  }

  public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();

    if (_ignore) {
      return;
    }
    _ignore = true;

        /*
         * To fix bug 24518 related to setting parameters of the form
         * {namespaceuri}localName which will get mapped to an instance
         * variable in the class.
         */
    final String name = BasisLibrary.mapQNameToJavaName(_name.toString());
    final String signature = _type.toSignature();
    final String className = _type.getClassName();

    if (isLocal()) {
            /*
              * If simple named template then generate a conditional init of the
              * param using its default value:
              *       if (param == null) param = <default-value>
              */
      if (_isInSimpleNamedTemplate) {
        il.append(loadInstruction());
        BranchHandle ifBlock = il.append(new IFNONNULL(null));
        translateValue(classGen, methodGen);
        il.append(storeInstruction());
        ifBlock.setTarget(il.append(NOP));
        return;
      }

      il.append(classGen.loadTranslet());
      il.append(new PUSH(cpg, name));
      translateValue(classGen, methodGen);
      il.append(new PUSH(cpg, true));

      // Call addParameter() from this class
      il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
          ADD_PARAMETER,
          ADD_PARAMETER_SIG)));
      if (className != EMPTYSTRING) {
        il.append(new CHECKCAST(cpg.addClass(className)));
      }

      _type.translateUnBox(classGen, methodGen);

      if (_refs.isEmpty()) { // nobody uses the value
        il.append(_type.POP());
        _local = null;
      } else {              // normal case
        _local = methodGen.addLocalVariable2(name,
            _type.toJCType(),
            il.getEnd());
        // Cache the result of addParameter() in a local variable
        il.append(_type.STORE(_local.getIndex()));
      }
    } else {
      if (classGen.containsField(name) == null) {
        classGen.addField(new Field(ACC_PUBLIC, cpg.addUtf8(name),
            cpg.addUtf8(signature),
            null, cpg.getConstantPool()));
        il.append(classGen.loadTranslet());
        il.append(DUP);
        il.append(new PUSH(cpg, name));
        translateValue(classGen, methodGen);
        il.append(new PUSH(cpg, true));

        // Call addParameter() from this class
        il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
            ADD_PARAMETER,
            ADD_PARAMETER_SIG)));

        _type.translateUnBox(classGen, methodGen);

        // Cache the result of addParameter() in a field
        if (className != EMPTYSTRING) {
          il.append(new CHECKCAST(cpg.addClass(className)));
        }
        il.append(new PUTFIELD(cpg.addFieldref(classGen.getClassName(),
            name, signature)));
      }
    }
  }
}
